Antibacterial and biodegradable extracting container

ABSTRACT

An antibacterial, biodegradable extracting container has a filtering surface formed from a water-permeable woven or knitted fabric formed from fibers comprising, as a principal component, an antibacterial, biodegradable polylactate polymer, and having a thickness of 1 to 100 dtex, wherein, preferably, the filtering surface is formed from the woven fabric having a cover factor K of 1600 to 6400, determined in accordance the following equation: 
     
       
           K =( N ×( A ) 1/2   /T )+( M ×( B ) 1/2   /S ) 
       
     
     wherein, N=warp density (yarns/10 cm), M=weft density (yarns/10 cm), A=thickness (dtex) of the warp yarns, B=thickness (dtex) of the weft yarns, T=specific gravity of the warp yarns and S=specific gravity of the weft yarns.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of International application numberPCT/JP00/08752, filed Dec. 11, 2000, which in turn claims priority ofJapanese application number 2000/5784, filed Jan. 6, 2000.

TECHNICAL FIELD

The present invention relates to a biodegradable extracting container.More particularly, the present invention relates to a biodegradableextracting container for extracting a drink material, for example,coffee, black tea, green tea, or oolong tea, with hot water or coldwater.

BACKGROUND ART

In conventional extracting bags for extracting a drink material, forexample, coffee, black tea, green tea or oolong tea with hot water orcold water, the bags are usually formed from woven fabrics, nonwovenfabrics comprising synthetic fibers selected from, for example, nylonfilaments and polyester filaments, or paper sheets.

After the synthetic fiber bags are used to extract the drink materialsuch as tea, the used bags are discharged as home waste. In this case,as the synthetic fibers from which the bags are formed, per se have nobiodegrability, the used bags are necessarily sent to a reclaimingtreatment or to a burning and then reclaiming treatment, and thisnecessity causes an increase in the amount of wastes which is currentlya social problem.

Compared with the synthetic fiber bags, the paper bags exhibits abiodegradability and thus the discharge of the used paper bags does notcause the above-mentioned problems.

When the drink material is contained in a bag formed from conventionalsynthetic fibers or paper sheets, and stored in storing surroundingshaving a high humidity and a high temperature, the problem such that inthe contained material in the bag, various molds and bacteria growthereon due to non-antibacterial property of the bag itself. In theprior art, to solve the above-mentioned problem, the bag is covered witha non-gas-permeable sheet by which the bag is protected from moisture.

For this covering, complicated and costly procedures are needed.

It is known that the anti-bacterial property can be imparted to thesynthetic fibers by knead-mixing an antibacterial agent into afiber-forming material during filament-forming procedures, or fixing theantibacterial agent on the surfaces of the filaments made by thefilament-forming procedures with a resinous binder. The above-mentionedapplication of the anti-bacterial agent to the synthetic fibers are notappropriately in view of the possibility of such an occurrence that theantibacterial agent is extracted into hot water or cold water during anextracting procedure, and the fragrance and safety of the extracteddrink are degraded.

Also, before the used extracting bag is discarded as a waste, theextraction residue in the bag is retained in a water-holding condition.During this stage, as the conventional fiber bag has no antibacterialproperty, various bacteria and molds are grown on portions of theresidual material contacting with water, and a slimy substance and anoffensive odor are generated. Therefor, when the used bag is dischargedas waste, a strong offensive odor is felt and a discharging operationbecomes difficult. Particularly, in the summer season, the bacteriavigorously propagate and, thus, there is a possibility of occurrence ofpoisoning through hands brought into contact with the waste.

As stated above, the extracting bag formed from the conventionalsynthetic fibers does not exhibit a biodegrading property and,therefore, when tea leaves contained and sealed in an extracting bag arestored, for the purpose of inhibiting the propagation of the variousmold and bacteria, the extracting bag is packaged with a water-proofsheet. However, the above-mentioned packaging is disadvantageous in thatcomplicated and costly procedures are needed. Also, in this case, beforethe extracting bag is used, a procedure of removing the packaging sheetfrom the bag is needed, and the removed packaging sheet which iscompletely unnecessary for the extraction using the extracting bag mustbe discharging. Namely, the use of the packaging sheet isdisadvantageous in that a discharging procedure is needed and a waste isgenerated.

Also, with respect to the treatment of the used drink-extracting bags,it should be noted that, as the conventional synthetic fiber bags do nothave biodegradability, the used bag waste must be sent to a reclaimingtreatment or a burning and then reclaiming treatment. This necessitycauses an increase in the amount of waste.

Also, the conventional extracting bags formed from the synthetic fibersare disadvantageous in that various bacteria and molds propagate on theextraction residue in the used bags so as to cause slimy substances andoffensive odor are generated, and there is a possibility of occurrenceof poisoning through the hands contacting the used bags.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an antibacterial,biodegradable extracting container formed from an extract-filteringmaterial which can prevent propagation of bacteria and mold on thematerial contained in the container and to be subjected to extraction,and which, per se, is bio-degradable.

The antibacterial, bio-degradable extracting container of the presentinvention has a filtering surface formed from a water-permeable sheetselected from woven and knitted fabrics, and is characterized in thatfibers from which the water-permeable sheet is formed comprises, as aprincipal component, an antibacterial, biodegradable polylactatepolymer, and have a thickness of 1 to 100 dtex.

In the antibacterial, biodegradable extracting container of the presentinvention, the filtering surface may form at least a portion of surfacesof a bag-formed container.

In the antibacterial, biodegradable extracting container of the presentinvention, the water-permeable fabric sheet from which the filteringsurface is formed preferably has a cover factor K of 1600 to 6400,determined in accordance with the following equation:

K=(N×(A)^(1/2) /T)+(M×(B)^(1/2) /S)

wherein, N represents a warp density (yarns/10 cm), M represents a weftdensity (yarns/10 cm), A represents a thickness (dtex) of the warpyarns, B represents a thickness (dtex) of the waft yarns, T represents aspecific gravity of the warp yarns and S represents a specific gravityof the weft yarns.

BEST MODE OF CARRYING OUT THE INVENTION

The filtering surface of the antibacterial, biodegradable extractingcontainer of the present invention is formed from a water-permeablesheet selected from water-permeable woven and knitted fabrics formedfrom fibers comprising an antibacterial, biodegradable polylactatepolymer and having a thickness of 1 to 100 dtex.

In the present invention, the term “antibacterial property” refers to acharacteristic of preventing propagation of bacteria and molds on amaterial contained in the extracting container of the present inventionand to be subjected to extraction, namely, coffee particles or varioustypes of tea leaves.

Namely, the extracting container of the present invention has acharacteristic of controlling the propagation of bacteria and molds andexhibits a bactericidal activity value of O or more. The bactericidalactivity value is a parameter representing an antibacterial property,determined in JIS L 1902. When the bactericidal activity value is lessthan 0, the bacteria can propagate and thus the object of the presentinvention cannot be attained.

The antibacterial, biodegradable extracting container of the presentinvention has a filtering surface through which an extract solutionobtained by extracting the material contained in the container and to beextracted with cold water or hot water, is filtered. The filteringsurface is formed from a water-permeable sheet selected from woven andknitted fabrics. The fibers from which the woven and knitted fabrics areformed comprises, as a principal component, an antibacterial,biodegradable polylactate polymer, and has a thickness of 1 to 100 dtex.Preferably, 50% by weight or more of the fibers from which the filteringsurface of the water-permeable sheet are formed from the antibacterial,biodegradable polylactate polymer. More preferably, 100% by weight ofthe filtering surface-forming fibers are formed from the polylactatepolymer.

The polylactate polymer usable for the present invention is one preparedby polymerizing lactic acid or dimer lactide of lactic acid which isused as a monomer. The polymer may be selected from homopolymers ofoptical isomers D and L, copolymers of the optical isomers D and L witheach other or a mixture of the homopolymers and the copolymers.

For the purpose of imparting an antibacterial property to the extractingcontainer, the inventors of the present invention carried out anextensive study on various polymers, and, as a result, found that theabove-mentioned polylactate polymer exhibits an excellent antibacterialproperty and is optimum as a material for forming the extractingcontainer.

The fibers comprising, as a principle component, preferably in a contentof 50% by weight or more, the polylactate polymer may be in the form ofmultifilaments, monofilaments or staple fibers. The staple fibers may beemployed in the form of spun yarns, or in the form of composite yarnscomprising the staple fibers and the filaments. There is no limitationto the cross-sectional profile of the fibers and filaments. Usually, acircular cross-sectional profile is preferred. In consideration of themeaning and knitting property of the fibers, the flexibility andextracting property of the container (bag), extracting property of thecontainer and degree of filter leakage of the extract in the container,the thickness of the polylactate polymer fibers must be in the range offrom 1 to 100 dtex, preferably 5 to 50 dtex.

If the thickness is less than one dtex, while the resultantwater-permeable sheet exhibit a satisfactory flexibility, in thewater-permeable sheet selected from the woven and knitted fabrics,slippage of the yarns easily occurs, and when the woven or knittedfabric is constituted in an increased yarn density, the weaving andknitting efficiency is decreased, and the resultant fabric isdisadvantageous in that in the extracting procedure, clogging of thefiltering surface occurs and the filtering efficiency becomesunsatisfactory. Also, if the thickness is more than 100 dtex, theresultant water-permeable woven or knitted fabric exhibit an increasedstiffness and an insufficient flexibility, and when the weaving orknitting density is decreased for the purpose of increasing theflexibility of the fabric, the resultant fabric has large gaps betweenthe yarns, and allows the solid fraction in the container to leakthrough the filtering fabric surface during the extracting procedure,namely, a disadvantageous filter leaking phenomenon occurs.

In the case where, in the extracting container of the present invention,the water-permeable sheet produced from the polylactate polymer fibersis a woven fabric, the cover factor K is preferably 1600 to 6400, morepreferably 3200 to 4000. The cover factor K is determined in accordancewith the following equation.

K=(N×(A)^(1/2) /T)+(M×(B)^(1/2) /S)

wherein, K represents a cover factor of the woven fabric, N represents awarp density (yarns/10 cm), M represents a weft density (yarns/10 cm), Arepresents a thickness (dtex) of the warp yarns, B represents athickness (dtex) of the weft yarns, T represents a specific gravity ofthe warp yarns and S represents a specific gravity of the weft yarns, ofthe woven fabric. If the cover factor K of the woven fabric for thewater-permeable sheet is less than 1600, the filter leak in theextraction may be too much, and if the cover factor K is more than 6400,the clogging of the filtering surface may occur during the extraction.

In the extracting container of the present invention, there is nolimitation to the form and dimensions thereof, as long as the containeris provided with at least one filtering surface formed from thewater-permeable sheet as specified above. The container may be abag-formed container (bag) formed from the specific water-permeablesheet. The bag-formed container may be a extracting bag having onlyfront and back filtering surfaces, or another extracting bag havingfront and back filtering surfaces, right and left side gore filteringsurfaces and a bottom gore filtering surface. Further the extractingcontainer may be in the form of a polyhedron, for example, a tetrahedronor hexahedron (box-form), or a cylinder. In this case, the polyhydronalor cylindrical container must be provided with at least one extractingsurface formed from the water-permeable sheet specified in the presentinvention. Alternatively, the extracting container of the presentinvention may be provided with, in addition to the bag-formed containerformed from the specific water-permeable sheet, a supporting member ofthe bag-formed container.

Where the extracting container of the present invention is an extractingbag, the bag is produced by cutting the specific water permeable sheetinto a desired size, the cut sheet is folded double and two side edgesare bound by a heat melt-welding method or high frequency welding methodor ultrasonic welding method to form a bag, while a top edge ismaintained open, to provide an inlet for feeding a material to beextracted into the resultant bag. The material to be extracted is placedinto the bag, and the open top edge of the bag is sealed by theabove-mentioned welding method. The extracting container in another formcan be produced by using the specific water-permeable sheet as definedin the present invention by a conventional container-producing method.

A hanging member attached to the extracting bag comprises a hangingthread comprising, for example, twisted multifilament or monofilamentyarn or a spun yarn of staple fibers and a tag made from a sheetmaterial, for example, a paper sheet, and connected to a top end of thehanging thread. Preferably, the hanging thread and the tag are producedfrom a biodegradable material, for example, polylactate polymer orcellulose, to enable the hanging member attached to the extracting bagto be completely biodegraded.

The water-permeable sheet from which the filtering surface of theextracting container of the present invention is produced from syntheticfibers comprising, as a principal component, a polylactate polymer. Whenthe material to be extracted, for example, coffee particles or tealeaves, is wetted with water, or after the extraction is completed, thepolylactate polymer fibers in the filtering surface exhibit aperformance of preventing the propagation of the bacteria and moldsadhered to the wetted extracted material, and after the used extractingcontainer is discarded, the polylactate polymer fibers are biodegraded.Also, as the polylactate polymer has a melt-bonding property, thepolylactate polymer fiber sheet can be melt-bonded by the conventionalheat welding method, high frequency welding method, and ultrasonicwelding method. Accordingly, the extracting container of the presentinvention enables the material to be extracted, contained in thecontainer, to be maintained fresh during storage thereof withoutpackaging the material with a non-gas-permeable material, and afterusing, the propagation of saprogens, for example, staphylococcus aureusand pseudomonas aeruginosa, and molds and the generation of putrid odorand slimy substance. Also, when the extracting container is discardedafter use, the container is biodegraded by degradation bacteria in theearth and disappears. Namely, the polylactate polymer is hydrolysed tosplit the molecular chains thereof in the initial stage of thebiodegradation. The hydrolysis is carried out at an accelated rate underhigh temperature and high humidity conditions, and at a low rate at roomtemperature. After the splitting of the polymeric molecular chains hasprogressed to a certain extent, the hydrolysis product is furtherdecomposed by the action of the natural degradation bacteria, forexample, heat-resisting spore bacteria and/or anaerophytes. It is notedthat almost of all of the degradation bacteria exist in the earth andfew degradation bacteria exist in the air. Thus, the bacteria existingin the air substantially do not degrade the polylactate polymer.

The extracting container of the present invention can be rapidlybiodegraded, after use, by using a conventional compost treatmentapparatus available on trade. In this case, the compost treatment isusually carried out at a temperature of 45 to 100° C., preferably 50 to80° C. If the treatment temperature is less than 45° C., not only thedegradation rate may be too low, but also propagation of variousbacteria other than the degradation bacteria effective on thebiodegradation may be promoted and thus the treatment surroundings maybecome insanitary and the degradation bacteria may be affected by thenon-degradation bacteria. If the treatment temperature is more than 100°C., the handling and surroundings may be dangerous in view of preventionof disasters, and/or the degradation bacteria may die out. To adjust thetreatment temperature as mentioned above, a heater may be used or forcertain types of bacteria, or metabolic heat generated by thedegradation bacteria may be utilized.

The degradation bacteria usable for the compost treatment at arelatively high temperature as mentioned above are preferably selectedfrom thermophilic bacteria, for example, bacillus brevis.

EXAMPLES

The present invention will be further illustrated by the followingexamples.

Example 1

A plain woven fabric having a cover factor K of 3480 was produced fromwarp and weft yarns each consisting of a poly-L-lactate monofilamenthaving a thickness of 25 dtex and a specific gravity of 1.24, in a warpdensity of 465 yarns/10 cm and a weft density of 398 yarns/10 cm,scoured and finish-set. The woven fabric in the form of a wound roll wasslit into a width of 130 cm and subjected to a cut-sealing procedure byan ultrasonic method to prepare flat bags having dimensions of 65 mmlength×42 mm width. Extracting bags of the present invention wereobtained.

Example 2

A plain woven fabric having a cover factor K of 3730 was produced fromwarp and weft yarns each consisting of a poly-L-lactate monofilamenthaving a thickness of 25 dtex and a specific gravity of 1.24, in a warpdensity of 492 yarns/10 cm and a weft density of 433 yarns/10 cm,scoured and finish-set. The woven fabric in the form of a wound roll wasslit into a width of 130 cm and subjected to a cut-sealing procedure byan ultrasonic method to prepare flat bags having dimensions of 65 mmlength×42 mm width. Extracting bags of the present invention wereobtained.

Comparative Example 1

A plain woven fabric having a cover factor K of 2791 was produced fromwarp and weft yarns each consisting of a polyester monofilament having athickness of 28 dtex and a specific gravity of 1.38, in a warp densityof 374 yarns/10 cm and a weft density of 354 yarns/10 cm, scoured andfinish-set. The woven fabric in the form of a wound roll was slit into awidth of 130 cm and subjected to a cut-sealing procedure by anultrasonic method to prepare flat bags having dimensions of 65 mmlength×42 mm width. Comparative extracting bags were obtained.

Comparative Example 2

A plain woven fabric having a cover factor K of 3624 was produced fromwarp and weft yarns each consisting of a polyester monofilament having athickness of 28 dtex and a specific gravity of 1.38, in a warp densityof 512 yarns/10 cm and a weft density of 433 yarns/10 cm, scoured andfinish-set. The woven fabric in the form of a wound roll was slit into awidth of 130 cm and subjected to a cut-sealing procedure by anultrasonic method to prepare flat bags having dimensions of 65 mmlength×42 mm width. Comparative extracting bags were obtained.

Comparative Example 3

A comparative extracting bags were produced by the same procedures as inExample 1, except that in the plain woven fabric, the warp density waschanged to 213 yarns/10 cm, the weft density was changed to 181 yarns/10cm and the cover factor K of the fabric was changed to 1589.

Note: In Comparative Examples 1 and 2, the diameter of the polyesterfilaments was established at the same as that of the polylactatefilaments used in Examples 1 and 2.

Tea Leaf-extracting Performance Test

As tea leaves to be contained in the extracting bag, green tea leavesavailable in the trade were purchased, and sieved into a fraction notpassed through a sieve No. 30 and a fraction passed through a sieve No.50 and the sieve No. 30-not-passed fraction in an amount of 80% byweight was evenly mixed with the sieve No. 50-passed fraction in anamount of 20% by weight, in accordance with Hara and two others, “themeasurement method of tea product by standard sieves” CHA GI KEN, No.11, pages 45 to 49 (1958), to enhance the reproducibility of the filterleak property of fine tea leaves particles and the extracting property.The mixed tea leaves were placed in an amount of 2 g (±5%) weighed by aprecision balance in each extracting bag through a top opening of thebag.

In each of Examples 1 and 2 and Comparative Examples 1, 2 and 3, 30extracting bags containing the tea leaves were prepared, and subjectedto measurement and evaluation of the leaking property of fine particlesof the tea leaves through the bags, before extraction and afterextraction.

The extraction of the tea leaves contained in the extracting bags werecarried out in accordance with the standard tea examination method (hotwater-extracting method, and the amounts of the fine tea leaf particlesleaked through the extracting bags was determined by the followingtesting method.

The amounts of the fine tea leaf particles leaked through the bags weremeasured on each of the bags (dry) before extracting and the bags afterextracting. In each measurement of the amount of the leaked fineparticles before extracting, the bag was shaken 20 times in up-to-downdirections within a 300 ml beaker in such a manner that no particles arespattered to the outside of the beaker, to collect the fine particlesleaked through the bag in the beaker. The above-mentioned procedureswere repeated for another 4 bags in the same beaker, the collected fine,particles were mixed with distilled water, the mixture was filteredthrough a quantitative filter paper the dry mass of which was measuredbefore the test, the filter paper used was dried, an increase in weightof the filter paper was determined, and from the data, the amount of theleaked fine tea leaf particles per pag was calculated.

Separately, to determine the amount of the fine tea leaf particlesleaked through the bag after extracting, the extracted bag was carefullyplaced on a bottom of 300 ml beaker, 200 ml of hot water boiled for 5minutes were poured as fast as possible (within 20 seconds) into thebeaker, the bag was kept in a calmly sunk condition in the beaker for 5minutes, thereafter, the bag is taken up as fast as possible from thebeaker, the fine particles precipitated in the inside of the beaker wasfilter-separated through a quantitative filter paper No. 2 the weight ofwhich was determined before the testing, the filter paper was dried in adesiccator, then the mass of the filtered fine particles was determined.

The results are shown in Table 1.

TABLE 1 Amount of fine tea leaf particles leaked through tea bag Amountof leaked Amount of leaked fine particles fine particles The number ofbefore extraction after extraction measurements (Average, g/bag)(Average, g/bag) Example 1 5 times 0.0256 0.0699 Example 2 5 times0.0247 0.0645 Comparative 5 times 0.0292 0.0741 Example 1 Comparative 5times 0.0272 0.0717 Example 2 Comparative 5 times 0.0806 0.1088 Example3

Table 1 clearly shows that in Examples 1 and 2, the amount of the leakedfine particles was small. In Comparative Example 3, however, the amountof the leaked fine particles was large.

The extracting bags used in extraction in Examples 1 and 2 andComparative Examples 1 and 2 were subjected to the following degradationtest in compost.

Biodegradation Test in Compost

In this test, an aging compost treatment apparatus for about 40 daysfermentation, made by Nihon Seikosho was employed. The degradationproperty test was carried out in accordance with ISO/FDIS 14855, and thedegradation degree test was carried out in accordance with ISO/CD 16929.

The tea leaves-containing extracting bag after extraction was left on afilter paper under conditions of 25° C. and 65% RH for 24 hours, thenwas placed in a polyester net and embedded in the compost treatmentapparatus. During the test, as a degradation sample, a sample of tealeaves having a size of 1 mm or more, was collected.

The compost treatment was carried out at a compost temperature of 58°C., at a temperature of air of 58° C. passing through the composttreatment apparatus, at a flow rate of air of 600 liters/hour, in awater content in the compost of 60 to 43% at a water vessel temperatureof 70° C.

With respect to the degradation property of the extracting bag under thecompost treatment conditions, Table 2 shows tensile strength-retentionof the bag, Table 3 shows weight reduction of the bag and Table 4 showsmolecular weight-retention.

TABLE 2 Degradation property test of tea bag in compost treatmentapparatus Tensile-strength retention (%) Before Compost treatment periodtreatment 3 days 7 days 10 days 14 days Example 1 100 40 0 0 0 2 100 430 0 0 Comparative 1 100 94 92 91 90 Example 2 100 93 91 91 91

TABLE 3 Weight retention (%) Before Compost treatment period treatment 3days 7 days 10 days 14 days Example 1 100 99 100 57 15 2 100 100 100 6016 Comparative 1 100 100 100 100 100 Example 2 100 100 100 100 100

TABLE 4 Molecular weight retention (%) Before Compost treatment periodtreatment 3 days 7 days 10 days 14 days Example 1 100 72 39 20 10 2 10074 40 20 11 Comparative 1 100 100 100 100 100 Example 2 100 100 100 100100

In the test results shown in Tables 2 to 4, it was confirmed that theextracting bags of Examples 1 and 2 were biodegraded by the composttreatment. In Comparative Examples 1 and 2, however, the biodegradationof the comparative extracting bags were not confirmed.

Antibacterial Property Test

Each of the extracting bags of Examples 1 and 2 and Comparative Examples1 and 2 before extraction and after extraction was subjected to anantibacterial test in which the bactericidal activity of the bag wasmeasured in accordance with JIS-L1902, by using, as testing bacteria,Staphylococcus aureus ATCC 6538P and Pseudomonase areuginosa IF03080, toevaluate the antibacterial property of the bag.

From the test results of the extracting bag before extraction, thestorage performance of the tea leaves in the bag was evaluated. Also,from the test results of the extracting bag after extraction, thehygienic performance of the extracting bag was evaluated.

Also, the extracting bag after extraction of the tea leaves was leftstanding on a polyethylene sheet under conditions of 25° C. and 65% RH,and the generation of odor and slimy substance was checked andevaluated. The bactericidal activity test results of the extracting bagsbefore and after extraction are shown in Tables 5 and 6.

TABLE 5 Bactericidal activity test of extracting bag before extractionBactericidal activity Testing Staphylococcus aureus Pseudomonasebacteria ATCC 6538P areuginosa IF03080 Example 1 2.0 1.7 2 2.5 1.9Comparative 1 −2.8 −1.5 Example 2 −2.5 −1.7

TABLE 6 Bactericidal activity test of extracting bag after extractionBactericidal activity Testing Staphylococcus aureus Pseudomonasebacteria ATCC 6538P areuginosa IF03080 Example 1 1.9 1.5 2 1.9 1.6Comparative 1 −2.1 −1.3 Example 2 −2.2 −1.5

In the test results shown in Tables 5 and 6, it was confirmed that theextracting bags of Examples 1 and 2 exhibit an antibacterial propertynot only before extraction but also after extraction. Also, in the testin which the extracting bags were left standing on the polyethylenesheet, no offensive odor and no slimy substance were generated from andon the extracting bags of Examples 1 and 2 whereas, for the extractingbags of Comparative Examples 1 and 2, a slimy substance was generatedon, and an offensive odor was emitted from, the extracting bags.

INDUSTRIAL APPLICABILITY OF THE INVENTION

The extracting container of the present invention using awater-permeable sheet comprising polylactate polymer fibers has apractically sufficient extract-filtering performance, and exhibitsexcellent biodegradability and a superior antibacterial property to thematerial contained in the bag, not only before extraction and but alsoafter extraction.

Particularly, in the extracting container of the present invention, thewoven or knitted fabric comprising the antibacterial polylactate polymerfibers used to form the container, enables the propagation of molds andbacteria on the material contained in the container and to be extractedto be inhibited to enhance the storage performance of the material to beextracted, such as tea leaves, the generation of offensive odor andslimy substance on the material after extraction to be prevented, andthe extracting container to be biodegraded together with the extractedmaterial therein.

What is claimed is:
 1. An antibacterial, biodegradable extractingcontainer having a filtering surface formed from a water-permeable sheetselected from woven fabrics, wherein fibers from which thewater-permeable sheet is formed comprises, as a principle component, anantibacterial, biodegradable polyactate polymer, and have a thickness of1 to 100 dtex, and the water-permeable fabric sheet, from which thefiltering surface is formed, has a cover factor K of 1600 to 6400determined in accordance with the following equation; K=(N×(A)^(1/2)/T)+(M×(B)^(1/2) /S) wherein, N represents a warp density (yarn/10 cm),M represents a weft density (yarn/10 cm), A represents a thickness(dtex) of the warp yarns, B represents a thickness (dtex) of the weftyarns, T represents a specific gravity of the warp yarn and S representsa specific gravity of the weft yarns.
 2. The antibacterial,biodegradable extracting container as claimed in claim 1, wherein thefiltering surface forms at least a portion of surfaces of a bag-formedcontainer.